Team Does Not Finish The Stories In The Sprint

The issue I am facing right now is my team never finishes all the stories taken up in the sprint. This has been happening on a consistent basis since last 6 months. However, we have been able to establish a consistent velocity. As a PO, I should try to maximise the product increment but this is not happening. What should I actually do? 1. Force the team to take up more stories in the sprint to increase productivity and take a chance that the sprint remains incomplete? 2. Change the PBI priority so more "small" stories are developed to maximise product increment? 3. Do nothing and let the team continue the way it is performing?

Posted By - SW